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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of cold and warm compress therapy on tissue temperature in healthy dogs

Millard, Ralph P. January 1900 (has links)
Master of Science / Department of Clinical Sciences / James Roush / Objective – To measure the effect of cold and warm compress therapy on tissue temperature in healthy dogs. Design – Controlled, blinded, crossover study Animals – 10 healthy mixed breed dogs Procedures – Dogs were sedated with hydromorphone 0.1 mg/kg IV and diazepam 0.25 mg/kg IV. Thermocouple needles were inserted to 0.5 cm (superficial), 1.0 cm (mid) and 1.5 cm (deep) into a shaved, lumbar, epaxial region to measure tissue temperature. Cold 2° F (-16.8° C) and warm 117°F (47°C) compresses were applied with gravity dependence for periods of 5, 10 and 20 minutes. Control data was collected under identical sedation. Results – Mean temperature significantly decreased after 5 minutes of cold application at only the superficial depth. Application of cold for 10 and 20 minutes significantly reduced the temperature at all depths. Twenty minutes of cold application significantly decreased temperature at only the mid depth compared to 10 minutes of application. Warm compresses significantly increased temperature at all depths after 10 minutes of application. Temperatures associated with 20 minutes of warm application were not significantly different than 10 minutes of application. Conclusions – When utilizing these methods of cold and warm compression, minimum time of application should be 10 minutes. Minimal changes occur by increasing cold application to 20 minutes and no changes occur when increasing heat application to 20 minutes. There is minimal to no change at depths ≥ 1.5 cm when using this method of heat application. Changes in tissue temperature and side effects of application longer than 20 minutes and in the absence of mu agonist opioids require further evaluation.
2

A Real-Time Address Trace Compressor for Embedded Microprocessors

Huang, Shyh-Ming 03 September 2003 (has links)
Address trace compression represents that the address data, which are generated from the instruction fetch stage of the microprocessor, can be retrieved for later observation and analysis. This real time trace compression hardware is the primary component of real-time trace system. In this paper, we present how to design and implement this real-time address trace compressor. Address trace compressor is allowed to perform accurate, successive trace collection in an unlimited length and can be used in various embedded microprocessors without influencing the operation of the microprocessors. Also, it has abundant reconfigurable parameters that can be used to develop a cost-effective trace system. The experiment results show that this compressor can reach a higher compression ratio of 1:100. Hence, by utilizing this real-time compression technique, the trace depths of new trace system can be 20 times more than these existing in-circuit emulators.
3

Virtual-MIMO systems with compress-and-forward cooperation

Jiang, Jing January 2011 (has links)
Multiple-input multiple-output (MIMO) systems have recently emerged as one of the most significant wireless techniques, as they can greatly improve the channel capacity and link reliability of wireless communications. These benefits have encouraged extensive research on a virtual MIMO system where the transmitter has multiple antennas and each of the receivers has a single antenna. Single-antenna receivers can work together to form a virtual antenna array and reap some performance benefits of MIMO systems. The idea of receiver-side local cooperation is attractive for wireless networks since a wireless receiver may not have multiple antennas due to size and cost limitations. In this thesis we investigate a virtual-MIMO wireless system using the receiver-side cooperation with the compress-and-forward (CF) protocol. Firstly, to perform CF at the relay, we propose to use standard source coding techniques, based on the analysis of its expected rate bound and the tightness of the bound. We state upper bounds on the system error probabilities over block fading channels. With sufficient source coding rates, the cooperation of the receivers enables the virtual-MIMO system to achieve almost ideal MIMO performance. A comparison of ideal and non-ideal conference links within the receiver group is also investigated. Considering the short-range communication and using a channel-aware adaptive CF scheme, the impact of the non-ideal cooperation link is too slight to impair the system performance significantly. It is also evident that the practicality of CF cooperation will be greatly enhanced if a efficient source coding technique can be used at the relay. It is even more desirable that CF cooperation should not be unduly sensitive to carrier frequency offsets (CFOs). Thus this thesis then presents a practical study of these two issues. Codebook designs of the Voronoi VQ and the tree-structure vector quantization (TSVQ) to enable CF cooperation at the relay are firstly described. A comparison in terms of the codebook design complexity and encoding complexity is presented. It is shown that the TSVQ is much simpler to design and operate, and can achieve a favourable performance-complexity tradeoff. We then demonstrate that CFO can lead to significant performance degradation for the virtual MIMO system. To overcome it, it is proposed to maintain clock synchronization and jointly estimate the CFO between the relay and the destination. This approach is shown to provide a significant performance improvement. Finally, we extend the study to the minimum mean square error (MMSE) detection, as it has a lower complexity compared to maximum likelihood (ML) detection. A closed-form upper bound for the system error probability is derived, based on which we prove that the smallest singular value of the cooperative channel matrix determines the system error performance. Accordingly, an adaptive modulation and cooperation scheme is proposed, which uses the smallest singular value as the threshold strategy. Depending on the instantaneous channel conditions, the system could therefore adapt to choose a suitable modulation type for transmission and an appropriate quantization rate to perform CF cooperation. The adaptive modulation and cooperation scheme not only enables the system to achieve comparable performance to the case with fixed quantization rates, but also eliminates unnecessary complexity for quantization operations and conference link communication.
4

Video transmission over a relay channel with a compress-forward code design

Polapragada, Chaitanya 15 May 2009 (has links)
There is an increasing demand to support high data rate multimedia applications over the current day wireless networks which are highly prone to errors. Relay channels, by virtue of their spatial diversity, play a vital role in meeting this demand without much change to the current day systems. A compress-forward relaying scheme is one of the exciting prospects in this regard owing to its ability to always outperform direct transmission. With regards to video transmission, there is a serious need to ensure higher protection for the source bits that are more important and sensitive. The objective of this thesis is to develop a practical scheme for transmitting video data over a relay channel using a compress-forward relaying scheme and compare it to direct and multi-hop transmissions. We also develop a novel scheme whereby the relay channel can be used as a means to provide the required unequal error protection among the MPEG-2 bit stream. The area of compress-forward (CF) relaying has not been developed much to date, with most of the research directed towards the decode-forward scheme. The fact that compress-forward relaying always ensures better results than direct transmission is an added advantage. This has motivated us to employ CF relaying in our implementation. Video transmission and streaming applications are being increasingly sought after in the current generation wireless systems. The fact that video applications are bandwidth demanding and error prone, and the wireless systems are band-limited and unreliable, makes this a challenging task. CF relaying, by virtue of their path diversity, can be considered to be a new means for video transmission. To exploit the above advantages, we propose an implementation for video transmission over relay channels using a CF relaying scheme. Practical gains in peak signal-to-noise ratio (PSNR) have been observed for our implementation compared to the simple binary-input additive white Gaussian noise (BIAWGN) and two-hop transmission scenarios.
5

Investigation on the Compress-and-Forward Relay Scheme

Zhang, Jie January 2012 (has links)
The relay channel plays an integral role in network communication systems. An intermediate node acts as a relay to facilitate the communication between the source and the destination. If the rate of codewords is less than the capacity of the source-relay link, the relay can decode the source's messages and forward them to the destination. On the contrary, if the rate of codewords is greater than the capacity of the source-relay link, the relay cannot decode the messages. Nevertheless, the relay can still compress its observations and then send them to the destination. Obviously, if the relay-destination link is of a capacity high enough such that the relay's observations can be losslessly sent to the destination, then the maximum message rate can be achieved as if the relay and the destination can jointly decode. However, when the relay-destination link is of a limited capacity such that the relay's observation cannot be losslessly forwarded to the destination, then what is the maximum achievable rate from the source to the destination? This problem was formulated by Cover in another perspective [7], i.e., what is the minimum rate of the relay-destination link such that the maximum message rate can be achieved? We try to answer this Cover's problem in this thesis. First, a sufficient rate to achieve the maximum message rate can be obtained by Slepian-Wolf coding, which gives us an upper bound on the optimal relay-destination link rate. In this thesis, we show that under some channel conditions, this sufficient condition is also necessary, which implies that Slepian-Wolf coding is already optimal. Hence, the upper bound meets exactly the minimum value of the required rate. In our approach, we start with the standard converse proof. First, we present a necessary condition for achieving the maximum message rate in the single-letter form. Following the condition, we derive a theorem, which is named as "single-letter criterion". The "single-letter criterion" can be easily utilized to verify different channels. Then we show that for two special cases: when the source-relay link and the source-destination link of the relay channel are both binary symmetric channels (BSCs), and when they are both binary erasure channels (BECs), Slepian-Wolf coding is optimal in achieving the maximum message rate. Moreover, the maximum message rates of these two special channels are also calculated in this thesis.
6

Video transmission over a relay channel with a compress-forward code design

Polapragada, Chaitanya 15 May 2009 (has links)
There is an increasing demand to support high data rate multimedia applications over the current day wireless networks which are highly prone to errors. Relay channels, by virtue of their spatial diversity, play a vital role in meeting this demand without much change to the current day systems. A compress-forward relaying scheme is one of the exciting prospects in this regard owing to its ability to always outperform direct transmission. With regards to video transmission, there is a serious need to ensure higher protection for the source bits that are more important and sensitive. The objective of this thesis is to develop a practical scheme for transmitting video data over a relay channel using a compress-forward relaying scheme and compare it to direct and multi-hop transmissions. We also develop a novel scheme whereby the relay channel can be used as a means to provide the required unequal error protection among the MPEG-2 bit stream. The area of compress-forward (CF) relaying has not been developed much to date, with most of the research directed towards the decode-forward scheme. The fact that compress-forward relaying always ensures better results than direct transmission is an added advantage. This has motivated us to employ CF relaying in our implementation. Video transmission and streaming applications are being increasingly sought after in the current generation wireless systems. The fact that video applications are bandwidth demanding and error prone, and the wireless systems are band-limited and unreliable, makes this a challenging task. CF relaying, by virtue of their path diversity, can be considered to be a new means for video transmission. To exploit the above advantages, we propose an implementation for video transmission over relay channels using a CF relaying scheme. Practical gains in peak signal-to-noise ratio (PSNR) have been observed for our implementation compared to the simple binary-input additive white Gaussian noise (BIAWGN) and two-hop transmission scenarios.
7

A Count-Based Partition Approach to the Design of the Range-Based Bitmap Indexes for Data Warehouses

Lin, Chien-Hsiu 29 July 2004 (has links)
Data warehouses contain data consolidated from several operational databases and provide the historical, and summarized data which is more appropriate for analysis than detail, individual records. On-Line Analytical Processing (OLAP) provides advanced analysis tools to extract information from data stored in a data warehouse. Fast response time is essential for on-line decision support. A bitmap index could reach this goal in read-mostly environments. When data has high cardinality, we prefer to use the Range-Based Index (RBI), which divides the attributes values into several partitions and a bitmap vector is used to represent a range. With RBI, however, the number of records assigned to different ranges can be highly unbalanced, resulting in different search times of disk accesses for different queries. Wu et al proposed an algorithm for RBI, DBEC, which takes the data distribution into consideration. But the DBEC strategy could not guarantee to get the partition result with the given number of bitmap vectors, PN. Moreover, for different data records with the same value, they may be partitioned into different bitmap vectors which takes long disk I/O time. Therefore, we propose the IPDF, CP, CP* strategies for constructing the dynamic range-based indexes concerning with the case that data has high cardinality and is not uniformly distributed. The IPDF strategy decides each partition according to the Probability Density Function (p.d.f.). The CP strategy sorts the data and partitions them into PN groups for every w continuous records. The CP* strategy is an improved version of the CP strategy by adjusting the cutting points such that data records with the same value will be assigned into the same partition. On the other hand, we could take the history of users' queries into consideration. Based on the greedy approach, we propose the GreedyExt and GreedyRange strategies. The GreedyExt strategy is used for answering exact queries and the GreedyRange strategy is used for answering range queries. The two strategies decide the set of queries to construct the bitmap vectors such that the average response time of answering queries could be reduced. Moreover, a bitmap index consists of a set of bitmap vectors and the size of the bitmap index could be much larger than the capacity of the disk. We propose the FZ strategy to compress each bitmap vector to reduce the size of the storage space and provide efficient bitwise operations without decompressing these bitmap vectors. Finally, from our performance analysis, the performance of the CP* strategy could be better than the CP strategy in terms of the number of disk accesses. From our simulation, we show that the ranges divided by the IPDF and CP* strategies are more uniform than those divided by the DBEC strategy. The GreedyExt and GreedyRange strategies could provide fast response time in most of situations. Moreover, the FZ strategy could reduce the storage space more than the WAH strategy.
8

Joint Distributed Detection and Estimation for Cooperative Communication in Cluster-Based Networks

Pu, Jyun-Wei 11 August 2008 (has links)
In this thesis, a new scheme based on the concept of compress-and-forward (CF) technique has been proposed. And expectation maximization (EM) algorithm is utilized to attain the aim of converging to a local optimum solution. According to the characteristic of EM algorithm, destination node would feed back a better decision to the relay node to be the next initial value. After the iteration, relay node would obtain a better detection result which would converge to a local optimum performance. At last the destination node would receive the optimum detection result from each relay and make a final decision. In the new structure, channel estimation can also be made at the relay node by EM algorithm, which is the reason why it is called joint distributed detection and estimation. Simulation shows that the proposed scheme would acquire an iteration gain at both the relay and destination node.
9

Investigation on the Compress-and-Forward Relay Scheme

Zhang, Jie January 2012 (has links)
The relay channel plays an integral role in network communication systems. An intermediate node acts as a relay to facilitate the communication between the source and the destination. If the rate of codewords is less than the capacity of the source-relay link, the relay can decode the source's messages and forward them to the destination. On the contrary, if the rate of codewords is greater than the capacity of the source-relay link, the relay cannot decode the messages. Nevertheless, the relay can still compress its observations and then send them to the destination. Obviously, if the relay-destination link is of a capacity high enough such that the relay's observations can be losslessly sent to the destination, then the maximum message rate can be achieved as if the relay and the destination can jointly decode. However, when the relay-destination link is of a limited capacity such that the relay's observation cannot be losslessly forwarded to the destination, then what is the maximum achievable rate from the source to the destination? This problem was formulated by Cover in another perspective [7], i.e., what is the minimum rate of the relay-destination link such that the maximum message rate can be achieved? We try to answer this Cover's problem in this thesis. First, a sufficient rate to achieve the maximum message rate can be obtained by Slepian-Wolf coding, which gives us an upper bound on the optimal relay-destination link rate. In this thesis, we show that under some channel conditions, this sufficient condition is also necessary, which implies that Slepian-Wolf coding is already optimal. Hence, the upper bound meets exactly the minimum value of the required rate. In our approach, we start with the standard converse proof. First, we present a necessary condition for achieving the maximum message rate in the single-letter form. Following the condition, we derive a theorem, which is named as "single-letter criterion". The "single-letter criterion" can be easily utilized to verify different channels. Then we show that for two special cases: when the source-relay link and the source-destination link of the relay channel are both binary symmetric channels (BSCs), and when they are both binary erasure channels (BECs), Slepian-Wolf coding is optimal in achieving the maximum message rate. Moreover, the maximum message rates of these two special channels are also calculated in this thesis.
10

The Realization Analysis of SAR Raw Data With Block Adaptive Vector Quantization Algorithm

Yang, Yun-zhi, Huang, Shun-ji, Wang, Jian-guo 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In this paper, we discuss a Block Adaptive Vector Quantization(BAVQ) Algorithm for Synthetic Aperture Radar(SAR). And we discuss a realization method of BAVQ algorithm for SAR raw data compressing in digital signal processor. Using the algorithm and the digital signal processor, we have compressed the SIR_C/X_SAR data.

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